Antistick electromagnet with armatures



Dec. 20, 1949 6. w. HOPKaNSON, JR 294919895 ANTISTICK ELECTROMAGNET WITH ARMAITURES;

Filed Aug. ll, 1948 IN V EN TOR. 041145,? M HOPKZ'MSOM JR.

- r-702M945: I

Patented Dec. 20, 1949 UNITED ANTISTICK ELECTROMAGNET WITH ARMATUBES Oliver W. Hopkinson, J r., Brackenridge, Pa.

Application August 11, 1948, Serial No. 43,744

Claims.

This invention relates to magnetic contactors such as electric circuit makers and breakers.

It is among the objects of this invention to provide a magnetic contactor in which sticking electric contacts cannot prevent the contactor from opening.

In accordance'with this invention an electromagnet is mounted adjacent the free end of a pivotally mounted arm. When the magnet is en-' ergized, the arm is attracted toward it and closes electric contacts in an electric circuit that is controlled by the movements of the arm. 'When the When the coil of the magnet is energized, the

striker is drawn back into the core passage to space its front end from-the arm that engages the front end of the core. A driving member is disposed at the rear end of the striker for driving y it forward when the coil is deenergized. When this happens the striker hits the arm and knocks it away from the magnet, even though the contacts tend to stick together. The driving member may take various forms. form of a solenoid core which is drawn up in a vertical passage in a solenoid coil above the rear end of the striker projecting from the. electromagnet. In such a case, when both coils are deenergized the vertical core will drop down and push the striker forward. Or; the'dr'iving member may be acoil spring compressed behind the striker for driving it forward when the electromagnet is de'energized.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a side view of my magnetic contactor closed; Fig. 2 is a vertical section taken on the line II--II of Fig. 1; Fig. 3

is a View similar to Fig. 1, but with the contactor open; and Fig. 4 is a fragmentary side view of a modification with the contactor closed.

Referring to Figs. 1 and 2 of the drawings, a platform I is provided with a central depending lug 2 having a pivot pin 3 projecting from its opposite sides into suitable supports 4. The platform carries electric contacts 6 that engage fixed contacts I supported at one side of the platform in any suitable manner. These contacts are connected in the electric circuit or circuits to be controlled. Rigidly mounted on the center of the platform is the lower end of an upright arm It maybe in the 2 8. The upper end of the arm has above the plat form a side contact face 9 that is shown engaging the front end of the upper leg of a stationary U-shape core 10 disposed above the platform. Wound around this upper leg of the core is an electric coil II to form an electromagnet. Consequently, when this coil is energized, the contact face of the arm is attracted to the front end of the core at the center of the coil, whereby the arm swings the contacts on the platform into engagement with the stationary contacts. When the coil is deenergized, the off-center weight of the arm is supposed to cause it to swing away from the magnet in order to separate the contacts, as shown in Fig. 3. However, occasionally the contacts weld themselves together sufiiciently to prevent the arm from separating them, and thus maintain the circuit closed.

It is a feature of this invention that means is provided for positively swinging the arm away from the coil when it is deenergized, even though the contacts otherwise would have stuck together. Accordingly, the upper leg of the core is provided with an axial passage it through it in -tvhich a striker is slidably mounted. This striker has the same cross sectional shape as the passage,

preferably square. The striker has a solid metal body [5 which is somewhat shorter than the coil so that when the body is centered therein the :"front end of the striker will be spaced from the front face of the core. Secured to opposite sides of the body of the striker are a pair of strips or legs l6 that extend out of the rear end of the core passage. These legs may be metal or any these legs are preferably inclined upward and forward."

Rigidly mounted above the projecting rear end of the striker is a second coil 25.! which has a vertical passage through it.

slidably mounted in this passage is a core-like driving member 2! that most suitably is rectangular in cross section. It is drawn up in the coil when the latter is energized. The lower front corner of the driving "member is beveled off to form an inclined surface 22 having the same inclination'as the rear end of the striker below it. The position of the driving member is such that when it moves downward the lower edge of its inclined surface 22 will overlap and engage the upper end of the inclined rear end I] of the striker and then slide down that surface, which will push the striker forward in the core. To limit forward movement of the striker,- its rear end may be provided with a downwardly projecting pin 23 that extends The rear ends I! .of l

engagement with the back side of the dropping driving member 2| to prevent it from binding in coil 20.

In operation, the two coils generally are connected in the samecircuit so thatwhen the main coil II is deenergized, the second coil 26 will be deenergized at the same time. When this occurs, the driving member 2| is released and drops by gravity onto the inclined rear-.endJ'L of the. striker. The impact drives the striker forward in core It so that the front end of the striker is caused to strike the contact face 9 of the arm and knock it away from the core if sticking-contacts; have tended to hold it there. Tosecure the desired impact, the driving member may bet-"prom vided with extra weight, such as by mounting a 2 VertioaLpin-Z'I. in its: upper-end and placingsthe -i desiredrmember of perforated weightszt on that: pin-v When thecoils-are energized againthe driving member 2 L is drawn up in upper. coil'l2ii,

when the second coil is energized, the lower end of said member and the rear end of the striker being adjacent each other, and at least one of said adjacent ends having an inclined surface for engaging the other so that when the coils are deenergized the impact of the falling driving member against the rear end of the striker will drive the striker forward to knock said arm away from said core.

2 A magnetic contactoix comprising: a pivotally mounted arm having a free end made of magnetic material, an electric coil adjacent the free end. of. the arm a .core of magnetic material in theacoil'foiattracting the free end of the arm when the coil is energized, the core being provided with an 'axial passage therethrough, a metal striker. slidablymounted in said passage with its front end withdrawn therein and its rear end projecting mherefrom when the coil is energized, at least a portion of the strikr in said passage being made-0t magnetie-materiaL-a se'oondcoil mounted above thetrear: endiofi the striker and provided.

with a vertical .passagepand -a driving. member of :ma'gnetic material drawn :upeinsaid verticalv andthestrikerbody-154s drawnzback into thec passage when the-second .coil is energized, the

passage in-the stationary .core w At the same: time;-:of-.co.urse,.the contactfaceS of the. arm is. drawn against the upper'end of thecore to close thecontacts fi and 1.-

lower end of said member and the reanend ofthe.

striker being. adjacent each other,.and-.said.-adjacent ends having-. upwardlyand= .forwardly-. inclined surfacesadapted to: slide againsteach other In the'modi-fication shown inFigwL-only a main. whentithe coils. are -deenergized. and the-driving coil-3 I .isused. In-this case'therdriving member is .inzthe form-0f a coil spring 32 which :is cOrn-wpressed betweenwthereanend of a short metal strikeri33 and a plate that-closes. therreanendw member: drops rwherebythe driving memberavill drivetherstriker forward to-knocksaid arm away from saidecorer.

3.-A magnetio-contactor comprising a pivotally of the passage -36 through the-upper leg of the mountedsarm. lhavingaa free. end made of magcore 31; Whenthe coil is energized,-the-strikers is pulled back in the passage 'far=enoughoto=space= its front end a short distanceufrom the contact 1 face of the pivotally-mounted-arm 38m Whenthe neti-c materiaLv an electric-coil adjacent the. free end of -the-arm-,-a core of magnetic material .inthe coil for-attracting ..the.-free end -of the arms. whenothewcoil is energizedythe core being. pro-s the"- striker-backdisappears, so thecoil spring drives the striker forward-against: the arm to swingit away'from the coreandthereby separate the electric:contacts Mkand-dla v It=wi11-be'n0ted' strikenslidably' mounted-in; said .passagev with its frontzend spaced from said arm .anditsrear endv projecting ,from-the core when-the-coil isener- A that-the striker m0ves:a short.distance:beforeit'AM-magnetic ma eriabirrhe cor andh rizon liy strikes the-arm; like a hammerw and=- that the striker: and spring "do" not exert: any; pressure against the arm while it is engaging: .the "core/ This isrbecause the spring compressed by "the strikerrwhjchvis withdrawn into the core bymaga; --'1}terialadrawn.upinsaidyerticatpassagewhen.the h second cellist-energized; the lowereend 'ofrsaid neti'c attraction.

According? to. the provisionsof :the patent statutes; I have explained the? principle ofinyin vention :and have illustrated and "described what" I nowi'consider to:representlits'i-best embodiment-@552 Hoiwever; 'I desire: rtorhave it." 'understood fthatgxr within the scope of the appended claims, the'zims" vention may bepracticedotherwise than' as spec-i fically i'llustrated andrdescribed.

I claim? 00 1. A magnetic contactor comprising. a pivota'lly mounted-arm havingza free end madefofmagnetic material, an electric coil :adjacentthe freezend of the-arm; a core of magnetic material'in. the" spaced-legs; projecting from: the. rearend- 01- said passage,:-a secondvcoil mounted' above the-arcan end or the striker-and provided with a vertical l passage; and a driving .:member ofmagnetic anamembenandsthe'rear end oi the striker being:ad-.- jacentzeaclrbtherpand at least. one-of said adjae cenirlendsrhavingan inclined surfa-ceior engaging .thetoth'ersdthatzwhenitheicoils1 aredeenergized theimpactiof. the:faliing. drivingi member against the rezmaendz bfrtherstrikenwilli drive the striker forward to knock said arm awayzf-rom said cora- 4. '='A.. mag-netic. conta'ctor comprising a pivotally mounted arm havinga f-reesend made of magnetic materialan electric 'coil adjacent-the freeend of the-arm, a *core of. magnetic material-in the coil-forattracting"thefreeend or-the arr i when the.-coilis energized-the core/being provided with coil for attracting: the free endoithearm when am axial passage-'therethroughra Striker 5116193013 the coil is energized,- the'eore' being provided with an .axial passage therethrough, a strike; islidably mounted in said passage with its front end-spaced from said-arm and its-rear.- end-proiect-ing. from the core when-the coil is energized, at least a por-- 7 0 neticlm'aterial drawn up. in .saidnverticalmassage-- mounted insaidpassage with its tirontendspace-l fromisaid-armaand. its rear endaproi-ectingfrom the. core: when -.the. coil. is energized, at least a portion'of. the striker. in saidrpassage being made .of magnetic. material. a bracket projectingfrom...

theback of. the core and provided with a .horizontalslot-in linewith said passage, a pin-projecting. from the.- rear. end. of. the striker. into said. slot ioialimitingiorward movement oflthe striker,

:a second.=.coil mounted. above thereau-end of..tlie.

striker and provided with a vertical passage, and a driving member of magnetic material drawn up in said vertical passage when the second 'coil is energized, the lower end of said member and the rear end of the striker being adjacent each other, and at least one of said adjacent ends having an inclined surface for engaging the other so that when the coils are deenergized the impact of the falling driving member against the rear end of the striker will drive the striker forwa' to knock said arm away from said core.

5. A magnetic contactor comprising a pivotally mounted arm having a free end made of magnetic material, an electric coil adjacent the frg? "end of the arm, a core of magnetic materia coil for attracting the free end of the ar the coil is energized, the core being provided with an axial passage therethrough, ajjstrik'er slidably mounted in said passage with its front end spaced from said arm and its rear end'projecting from the core when the coil is energized, at least a portion of the striker in said passage being made of magnetic material, a seconds-ch11 mounted above the rear end of the striker;v and provided with a vertical passage, a driving mem- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 682,377 Wurmb Sept. 10, 1901 2,090,522 Sippel Aug. 17, 1937 2,324,642 Peterson July 20, 1943 2,347,369 Roters Apr. 25, 1944 2,405,761 Simmie Aug. 13, 1946 2,414,476 Mathes Jan. 21, 1947 

